Patent GB-713974-A (GB)
Title: Improvements in gear-changing devices for motor vehicles
IPC: B62M25/04
Filed: 1952-01-21
Abstract: 713,974. Controlling change-speed gearing. AUTO UNION GES. Jan. 21, 1952 [Jan. 20, 1951], No. 1713/52. Class 80 (2) [Also in Group XXXI] A gear-changing device, for motor-vehicle change-speed gearing of the kind which itself embodies clutch means and in which the change from one gear ratio to another is effected by operating these clutch means/comprises, in combination, a twist grip 2 adapted, upon being manually rotated, to effect pre-selection only of the desired gear ratio, and a pivotal handle 3 associated with clutch operating means, the hand lever being arranged so as to be capable of being pivotally moved, at the same time as the twist grip is rotated, and means such as a cam follower co-operating with the twist grip and the hand lever and adapted, when the pivotal movement of the latter is effected approximately concomitantly with said rotation of the twist grip, so to control the pivotal movement as to cause the clutch means to be engaged gradually. The clutch means remains engaged after the hand lever has been released and returned to its original position by a spring 24, while rotation of the twist grip in the opposite direction causes the clutch means to be disengaged. The device is shown applied to a motor-cycle handle bar 1, with the handle 3 pivoted thereto, although it may also be mounted on the twist grip for rotation therewith. The cam 4, having recesses 5, 6, is rigidly connected to the twist grip and engages the cam follower 8 on a reciprocable spindle 7, having a collar 9 at one end, co-operating with two sliding clutch operating members 10, 11 connected by cables to a clutch operating finger 22. The clutch operating members 10, 11 have ribs 14, 15 which can engage in relatively wide slots 17, 18 in a ring 16 mounted to rotate with the twist grip 2 but to be axially slidable therein by the hand lever 3, against the pressure of the spring 24. The twist grip 2 is rotated so that the slot 17 (or 18) is opposite the rib 14 (or 15) to preselect the gear, and the gear change is then established by operation of the hand lever 3 which moves the ring 16 to the left (as shown in the Figure) so that the clutch operating member 11 (or 10) is similarly moved to the left and the clutch operating member 10 (or 11) moves to the right as the rib 17 (or 18) enters the slot 14 (or 15), thus moving a clutch operating finger 22. The slots 14, 15 are made of considerable width so that the corresponding rib can begin to move to the right as soon as the operation is begun, simultaneous operation of the twist grip 2 and hand lever 3 causing the cam follower 8 to move slowly to the right along the cam surface into the recess 5 or 6 and thus produce gradual engagement of the chosen clutch. The hand lever 3 is then released, to allow the ring 16 to be moved back to the right by the spring 24 without affecting the engagement of the chosen gear clutch. To change back to neutral from the engaged position, the twist grip is rotated in the opposite sense to that used to engage the changespeed clutch, thus causing the cam follower 8 to ride out of the recess 5 or 6 and thereby draw the reciprocable spindle 7 to the left, and with it the sliding clutch operating member 10 or 11, and hence restore the position shown in Fig. 1.